This is very true, but you usually find this when it heavily stocked particularly with F1`s
As there no F1`s in there and the water is so deep giving a greater volume this particular lake can hold a reasonable head of carp according to the IE.
I was the bailiff of fishery in Anglesey until 12 months ago and it did have that exact problem, it is only just now getting the tench back after 2 years of nettings
Steve